The present invention relates to a management method (or inspection method) of manufacturing electronic components such as semiconductor wafers, printed boards, TFT liquid crystal display units, plasma display units and boards for magnetic disks with high yield and a production management system.
In the manufacturing of electronic components such as semiconductor wafers, printed boards, TFT liquid crystal display units, plasma display units and magnetic disk boards, such components are becoming more miniaturized and complicated every year, and it is very important to ensure a high yield.
Main causes of degrading the yield involve (1) extraneous substances or defects in external appearance (including unusual growth of crystal, disconnection, short circuit or broken portion) and (2) failure in pattern formation (failure in width of a pattern or the like) caused by alignment error, focusing error, unusual thickness or etching trouble. In the mass production of electronic components, these failures occur dispersedly (for example, the failures occur in one wafer per many wafers separately in the manufacturing of semiconductor wafers) or continuously (for example, the failures occur once every many wafers continuously in the manufacturing of semiconductor wafers).
In order to prevent the dispersed failures or continuous failures, heretofore, inspection is made in the main process of the manufacture to detect failures and countermeasures for coping with the failures are taken.
By way of example, JP-A-55-149829 and JP-A-59-65428 disclose many methods of detecting minute extraneous substances existing on electronic components such as semiconductor wafers having patterns formed thereon. Various inspection apparatuses using these detection methods are developed and used in the manufacturing line.
The problem that the present invention is to solve is now described by taking the inspection of extraneous substances on wafers and defects in external appearance as an example.
When the same wafer is inspected by inspection apparatuses A and B having different detection systems and failure distribution maps are prepared on the basis of the coordinates of detected failures such as extraneous substances and defects in external appearance, the respective failure distribution maps are expressed as chips 101a and 101b of FIGS. 1 and 2, respectively. When the two failure distribution maps are collated with each other (overlapped on each other) to examine failures, the failures such as extraneous substances and defects in external appearance detected by both the inspection apparatuses A and B can be understood to be black dots 102a and 102b. It can be understood that the failures such as extraneous substances and defects in external appearance detected separately by only the inspection apparatus A or B are hatched circles 103a and 103b and the failures which cannot be detected by the apparatus A or B are circles 104a and 104b.
Thus, when a Ben's diagram is prepared on the basis of data examined by collating failure distribution maps detected by inspection apparatuses A, B, C and D having different detection systems with one another, the Ben's diagram is prepared as shown in FIG. 3. The detected results of the inspection apparatuses A, B, C and D are represented by circles 10, 11, 12 and 13, respectively, and the failures such as extraneous substances and defects in external appearance detected by all of the inspection apparatuses irrespective of the inspection system are represented by an overlapped portion of the circles (hatched portion).
The detection ratios of the failures such as, particularly, minute extraneous substances and defects in external appearance having the lowest possible detection sensitivity are different depending on the different detection methods as shown in FIG. 3. Consequently, even when an inspection apparatus is introduced with much effort and inspection is made by the apparatus, fatal failures cannot be detected under certain circumstances and numerous failures may sometimes occur. Accordingly, it is very important to select an optimum inspection apparatus in order to attain the high yield.
Further, even when the inspection apparatus to be used is determined, the inspection frequency is almost determined by the sense and experience of the engineer engaged in the manufacturing line and accordingly this is a large factor of impeding automatization of the management of the inspection processes.